N-Protected Indigo Derivatives for Ring Dyeing Synthetic Textiles

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Solution Overview

Problem

Current indigo dyeing processes are unable to achieve the 'ring effect' on synthetic textiles like polyesters and polyamides due to their hydrophobic nature, which prevents the use of conventional indigo dyes in continuous industrial plants.

Innovation Solution

The use of N-protected indigo derivatives with sterically hindered hydrophobic protecting groups, such as t-Boc and Fmoc, which are susceptible to removal, provides a hydrophilic/hydrophobic balance, allowing these derivatives to dye synthetic textiles and achieve the 'ring effect' in conventional continuous indigo dyeing processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional indigo dyes are used for dyeing synthetic textiles in continuous industrial plants, then the dyeing process can be performed efficiently, but the hydrophobic nature of synthetic textiles prevents the dye from penetrating and achieving the desired 'ring effect'

Engineering Contradiction:
Improvedyeing process efficiencyVSAvoiddye penetration and ring effect achievement
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention modifies the chemical parameters of the indigo dye by introducing hydrophilic groups (such as sulfonate groups) to the indigo molecule. This parameter change alters the dye's solubility and interaction properties, enabling it to penetrate hydrophobic synthetic textile fibers while maintaining the ability to produce the desired ring effect. The modified dye structure allows it to function effectively in continuous industrial dyeing processes on synthetic materials like polyester and polyamide.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite dye structure that combines the hydrophobic indigo core (which provides the characteristic blue color and ring effect) with hydrophilic functional groups (which enable penetration into synthetic fibers). This composite molecular structure allows the dye to simultaneously interact with both hydrophobic fiber surfaces and aqueous dyeing solutions, resolving the contradiction between dye penetration and ring effect achievement.

Inventive Principle:
Principle #40Composite materials

2Reliability

If N-protected indigo derivatives with hydrophobic protecting groups are used, then the dye can interact with hydrophobic synthetic textile surfaces, but the protecting groups must be removed to achieve color change functionality

Engineering Contradiction:
Improveaffinity for synthetic textile surfacesVSAvoidadditional thermal treatment step for color change
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention applies protecting groups (such as t-Boc or Fmoc) to the indigo nitrogen atoms in advance of the dyeing process. These protecting groups are specifically chosen because they provide hydrophobic character that enhances affinity for synthetic textile surfaces during dyeing, yet they are designed to be removable under mild thermal conditions after dyeing. This preliminary protection strategy enables sequential optimization of both dyeing affinity and final color properties.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention introduces dynamic functionality to the dye system through thermally removable protecting groups. The dye molecule transitions from a protected state (with hydrophobic groups providing surface affinity) to an unprotected state (with color change capability) in response to thermal stimuli. This dynamic behavior allows the same dye molecule to serve multiple functions at different stages of the process and enables end-users to change the textile color on demand through simple heating.

Inventive Principle:
Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enables the dyeing of synthetic textiles with a 'ring effect' and allows for color change upon thermal treatment, providing a cost-effective and versatile solution for achieving desired colors in synthetic textile products.

Implementation Method 1

Jet dyeing is a batch process, leading to the penetration of dye molecules deep into yarns and fabrics... This deep penetration of the dye, makes this process not able to provide the 'ring effect' to the yarns (or 'surface dyeing' to the fabrics)

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

N-protected indigo dyed synthetic textiles possessing the 'ring effect' and colour changing capability upon heating

Methodology Applied
Scientific EffectThermal decomposition: Pyrolysis

Data Source

PatentEP3312337B1Use of indigo derivatives for dyeing synthetic textiles, novel indigo derivatives and process for dyeing synthetic textiles
Publication Date: 2019.04.03 SANKO TEKSTIL ISLETMELERI SANAYI VE TICARET AS
  • EP3312337B1 patent drawingFigure 1A~1D
  • EP3312337B1 patent drawingFigure 2
  • EP3312337B1 patent drawingFigure 3

AI summary

The present invention relates to the use of indigo derivatives for dyeing synthetic textiles to a process for dyeing synthetic textiles and to dyed textiles and articles containing them. The invention also relates to novel indigo derivatives per se and to a process for the preparation thereof.